Changing Motor Phase Terminations?

So I’ve been thinking of ways to lower my motors’ KV for a number of reasons. Firstly, the potential benefits:

  • Decreased top speed (mine is actually too high for me, I don’t think I’ve ever even used the top half of my throttle)
  • Decreased current draw - this should also cause an increase in range (?)
  • Better startup torque/amp (as a direct result of lower current draw)

I don’t want to buy new motors, and I’d like to avoid re-winding my phases, so what I’d like to do is change my motor phase terminations from Delta configuration:

To a Wye configuration:

(shitty MSPaint drawings for your viewing pleasure)

This change should result in a 1.7x lower KV value in the motor, thus incurring all the benefits stated above.

My question is, will this change have any issues with my ESC (Unity)? My guess is that it’ll still be completely compatible, but I want to check before I do it.


Will continue to work, but you have to do the motor detection again

Please post you how you did and some pictures since I will be doing that soon also :grin:


What kv are you trying to change from?

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im curious how you determined it was delta to begin with… usually there’s no way to tell from the outside…


Definitely will do, looking forward to the project!

Besides the fact that the majority of bldc’s are, mine are super open-air so you can literally see where the windings terminate on the phase wires.

580 - bought em a few years ago, didn’t realize how stupidly fast they’d be.


i find it’s interesting how the kv change factor is the square root of the conductance change factor when the km is constant


I find some aspects of bldc’s to be both fascinating and completely mind-boggling - like how someone figured out that Delta terminations have 1.7x the KV of Wye terminations. I’d be very intrigued to see why that is but everything I’ve found treats it as just a given.

graph it @Sharts


well when you change from delta to wye, your resistance will triple, which means your conductance will be 1/3 or 0.3333… and the change factor of your kv will be the square root of 0.3333 or 0.5773x


…which is 1/1.7! WHOA!


yes, the kv changes at the square root of the conductance changes with constant km (copper volume)…


My main doubt is how to identify what ends to weld together and which ones go out of the motor

I think with a winding diagram you can figure it out

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That is definitely important! From what I can see, the wires are currently run like so:

It doesn’t look like they’re soldered at all besides the bullet connections, so it should be as simple as removing the bullets, un-twisting the remaining wire, and cross-referencing with a winding diagram.


I’m an electronics noob, but is it possible to have all 6 wires come out of a motor and change the termination on the fly with relays, for a pseudo 2-speed “gearbox”?

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yea a switch to wye or delta can be made out of the motor but I think the esc would ideally or maybe necessarily need to have both variables in the programming and be able to switch as well

it is possible to convert delta to wye without opening the motor connecting the individual multistrands in series outside of the motor from phase to phase I hear. never done it


I’ve gotten started on the conversion - popped the motors open and started rearranging the wires for wye termination. I’ve just gotta remove the enamel on the wires and do a lot of continuity checks before I solder everything up and insulate. Last thing I want is a short :stuck_out_tongue:
I should be able to finish up and make a post some time tomorrow!


Did you remove the stator from the frame? For mine I’m really debating if I should just re terminate or do a complete rewind

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Removing the stator from the frame proved to be an incredibly difficult task, so I opted to not do that and just thread the wires around different parts of the frame to make them easier to manage.
Those things were glued together incredibly well.


Yeah, I will need to remove them, someone suggested a generous amount of heat is the key, think it was @rey8801

yes not diffiuclt once understood the trick. I removed at least 6 motors and the last 3-4 went super easy.